© Shutterstock 

What is bone marrow? -

Found inside the bones, marrow is a spongy material that contains stem cells.

© Shutterstock 

Two types of bone marrow -

In may surprise you to learn that there are two types of bone marrow: red and yellow.

© Shutterstock 

Red bone marrow -

Red bone marrow contains blood stem cells that can become red blood cells, white blood cells, or platelets.

© Shutterstock 

Yellow bone marrow -

Yellow bone marrow is made mostly of fat and contains stem cells that can become cartilage, fat, or bone cells. However, it may be converted to red marrow under certain conditions, such as severe blood loss or fever.

© Shutterstock 

Vital functions -

These cells play different but very important functions in keeping the body healthy and strong.

© Shutterstock 

Blood cell production -

Human bone marrow produces approximately 500 billion blood cells per day.

© Shutterstock 

The human body -

Bone marrow comprises approximately 5% of total body mass in healthy adult humans.

© Shutterstock 

Where is bone marrow located? -

Bone marrow is primarily located in the vertebrae, hips, breastbone, ribs, and skull, and at the ends of the long bones of the arm and leg.

© Shutterstock 

Bone marrow diseases and disorders -

In leukemia, a cancer of the blood, the bone marrow makes abnormal white blood cells.

© Shutterstock 

Lymphoma -

Lymphoma is a cancer of the lymphatic system, which develops when white blood cells called lymphocytes grow out of control.

© Shutterstock 

Multiple myeloma -

Multiple myeloma, also known as myeloma, is a type of bone marrow cancer that forms in a type of white blood cell called a plasma cell. Healthy plasma cells help you fight infections by making antibodies that recognize and attack germs.

© Shutterstock 

Myelodysplastic syndromes -

Myelodysplastic syndromes are conditions that can occur when the blood-forming cells in the bone marrow become abnormal.

© Shutterstock 

Aplastic anemia -

In aplastic anemia, the bone marrow doesn't make red blood cells.

© Shutterstock 

Stem cells -

With bone marrow diseases, there are problems with the stem cells or how they develop. As previously described, stem cells are special cells produced by bone marrow that can turn into different types of blood cells.

© Shutterstock 

Bone marrow transplant -

When it becomes necessary, a bone marrow transplant, also known as stem cell transplant, replaces damaged blood cells with healthy ones.

© Shutterstock 

Matching donors to patients -

A transplant can only be carried out after doctors match donors to patients based on their human leukocyte antigen (HLA) tissue type.

© Shutterstock 

Human leukocyte antigen -

HLA are proteins, or markers, found on most cells in your body. Your immune system uses these markers to recognize which cells belong in your body and which do not.

© Shutterstock 

Why is a bone marrow transplant needed? -

The aim of a bone marrow transplant is to cure disorders, diseases, and types of cancer previously described. A transplant will also regenerate a new immune system.

© Shutterstock 

Replacing stem cells -

If a patient is undergoing doses of chemotherapy or radiation needed to cure an existing cancer, a bone marrow transplant may be needed to replace stem cells permanently damaged or destroyed by the treatment.

© Shutterstock 

Complications -

A bone marrow transplant is not without its risks. Infections are likely in a patient with severe bone marrow suppression.

© Shutterstock 

Other risks -

Nonfunctioning bone marrow can result in thrombocytopenia (low platelets) and anemia (low red blood cells)—both life-threatening conditions.

© Shutterstock 

Respiratory distress -

The lungs and pulmonary system may be adversely affected during transplant as a result of respiratory distress, which may be compromised during the procedure.

© Shutterstock 

Organ damage -

Another risk associated with a bone marrow transplant is organ damage. The liver and heart can be damaged during the transplantation process. It's important to stress that each individual may experience symptoms differently, and to a dissimilar degree.

© Shutterstock 

Donating bone marrow -

In theory, you can donate many times, since your body can replace lost bone marrow.

© Shutterstock 

What disqualifies people from being a donor? -

People with chronic neck, back, hip, or spine pain cannot be donors. Those with autoimmune disorders are also disqualified from being a donor. And people aged 60 and older can’t be donors.

© Shutterstock 

Is the donation process painful? -

No. Around 70% of marrow donations use peripheral blood stem cell apheresis, a non-surgical procedure.

© Shutterstock 

Traditional method of harvesting marrow -

Around 30% of marrow donations are collected by healthcare providers using large, hollow needles that pull bone marrow from donors' hips (pelvic bones). It's a surgical procedure requiring a general anesthetic.

© Shutterstock 

Why donate? -

Each year, approximately 18,000 people in the United States alone learn they have a bone marrow disease that a bone marrow transplant or other stem cell transplant could cure.

© Shutterstock 

Finding a match -

According to statistics published by the Institute for Justice, only 30% of patients in the United States who need a bone marrow transplant have a matching donor in their families.

© Shutterstock 

Donating is safe -

Donating bone marrow is safe: bone marrow donation requires less than 5% of marrow cells, and more than 35,000 people have donated bone marrow to a stranger without a single donor death. 

Sources: (National Cancer Institute) (Johns Hopkins Medicine) (Cleveland Clinic) (Health Resources & Services Administration) (Institute for Justice)

See also: Celebrities you didn't know received organ donations

© Shutterstock